fs/xfs/scrub/refcount.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2017-2023 Oracle.  All Rights Reserved.
   4  * Author: Darrick J. Wong <[email protected]>
   5  */
   6 #include "xfs.h"
   7 #include "xfs_fs.h"
   8 #include "xfs_shared.h"
   9 #include "xfs_format.h"
  10 #include "xfs_log_format.h"
  11 #include "xfs_trans_resv.h"
  12 #include "xfs_mount.h"
  13 #include "xfs_trans.h"
  14 #include "xfs_ag.h"
  15 #include "xfs_btree.h"
  16 #include "xfs_rmap.h"
  17 #include "xfs_refcount.h"
  18 #include "scrub/scrub.h"
  19 #include "scrub/common.h"
  20 #include "scrub/btree.h"
  21 #include "scrub/trace.h"
  22 #include "scrub/repair.h"
  23
  24 /*
  25  * Set us up to scrub reference count btrees.
  26  */
  27 int
  28 xchk_setup_ag_refcountbt(
  29         struct xfs_scrub        *sc)
  30 {
  31         if (xchk_need_intent_drain(sc))
  32                 xchk_fsgates_enable(sc, XCHK_FSGATES_DRAIN);
  33
  34         if (xchk_could_repair(sc)) {
  35                 int             error;
  36
  37                 error = xrep_setup_ag_refcountbt(sc);
  38                 if (error)
  39                         return error;
  40         }
  41
  42         return xchk_setup_ag_btree(sc, false);
  43 }
  44
  45 /* Reference count btree scrubber. */
  46
  47 /*
  48  * Confirming Reference Counts via Reverse Mappings
  49  *
  50  * We want to count the reverse mappings overlapping a refcount record
  51  * (bno, len, refcount), allowing for the possibility that some of the
  52  * overlap may come from smaller adjoining reverse mappings, while some
  53  * comes from single extents which overlap the range entirely.  The
  54  * outer loop is as follows:
  55  *
  56  * 1. For all reverse mappings overlapping the refcount extent,
  57  *    a. If a given rmap completely overlaps, mark it as seen.
  58  *    b. Otherwise, record the fragment (in agbno order) for later
  59  *       processing.
  60  *
  61  * Once we've seen all the rmaps, we know that for all blocks in the
  62  * refcount record we want to find $refcount owners and we've already
  63  * visited $seen extents that overlap all the blocks.  Therefore, we
  64  * need to find ($refcount - $seen) owners for every block in the
  65  * extent; call that quantity $target_nr.  Proceed as follows:
  66  *
  67  * 2. Pull the first $target_nr fragments from the list; all of them
  68  *    should start at or before the start of the extent.
  69  *    Call this subset of fragments the working set.
  70  * 3. Until there are no more unprocessed fragments,
  71  *    a. Find the shortest fragments in the set and remove them.
  72  *    b. Note the block number of the end of these fragments.
  73  *    c. Pull the same number of fragments from the list.  All of these
  74  *       fragments should start at the block number recorded in the
  75  *       previous step.
  76  *    d. Put those fragments in the set.
  77  * 4. Check that there are $target_nr fragments remaining in the list,
  78  *    and that they all end at or beyond the end of the refcount extent.
  79  *
  80  * If the refcount is correct, all the check conditions in the algorithm
  81  * should always hold true.  If not, the refcount is incorrect.
  82  */
  83 struct xchk_refcnt_frag {
  84         struct list_head        list;
  85         struct xfs_rmap_irec    rm;
  86 };
  87
  88 struct xchk_refcnt_check {
  89         struct xfs_scrub        *sc;
  90         struct list_head        fragments;
  91
  92         /* refcount extent we're examining */
  93         xfs_agblock_t           bno;
  94         xfs_extlen_t            len;
  95         xfs_nlink_t             refcount;
  96
  97         /* number of owners seen */
  98         xfs_nlink_t             seen;
  99 };
 100
 101 /*
 102  * Decide if the given rmap is large enough that we can redeem it
 103  * towards refcount verification now, or if it's a fragment, in
 104  * which case we'll hang onto it in the hopes that we'll later
 105  * discover that we've collected exactly the correct number of
 106  * fragments as the refcountbt says we should have.
 107  */
 108 STATIC int
 109 xchk_refcountbt_rmap_check(
 110         struct xfs_btree_cur            *cur,
 111         const struct xfs_rmap_irec      *rec,
 112         void                            *priv)
 113 {
 114         struct xchk_refcnt_check        *refchk = priv;
 115         struct xchk_refcnt_frag         *frag;
 116         xfs_agblock_t                   rm_last;
 117         xfs_agblock_t                   rc_last;
 118         int                             error = 0;
 119
 120         if (xchk_should_terminate(refchk->sc, &error))
 121                 return error;
 122
 123         rm_last = rec->rm_startblock + rec->rm_blockcount - 1;
 124         rc_last = refchk->bno + refchk->len - 1;
 125
 126         /* Confirm that a single-owner refc extent is a CoW stage. */
 127         if (refchk->refcount == 1 && rec->rm_owner != XFS_RMAP_OWN_COW) {
 128                 xchk_btree_xref_set_corrupt(refchk->sc, cur, 0);
 129                 return 0;
 130         }
 131
 132         if (rec->rm_startblock <= refchk->bno && rm_last >= rc_last) {
 133                 /*
 134                  * The rmap overlaps the refcount record, so we can confirm
 135                  * one refcount owner seen.
 136                  */
 137                 refchk->seen++;
 138         } else {
 139                 /*
 140                  * This rmap covers only part of the refcount record, so
 141                  * save the fragment for later processing.  If the rmapbt
 142                  * is healthy each rmap_irec we see will be in agbno order
 143                  * so we don't need insertion sort here.
 144                  */
 145                 frag = kmalloc(sizeof(struct xchk_refcnt_frag),
 146                                 XCHK_GFP_FLAGS);
 147                 if (!frag)
 148                         return -ENOMEM;
 149                 memcpy(&frag->rm, rec, sizeof(frag->rm));
 150                 list_add_tail(&frag->list, &refchk->fragments);
 151         }
 152
 153         return 0;
 154 }
 155
 156 /*
 157  * Given a bunch of rmap fragments, iterate through them, keeping
 158  * a running tally of the refcount.  If this ever deviates from
 159  * what we expect (which is the refcountbt's refcount minus the
 160  * number of extents that totally covered the refcountbt extent),
 161  * we have a refcountbt error.
 162  */
 163 STATIC void
 164 xchk_refcountbt_process_rmap_fragments(
 165         struct xchk_refcnt_check        *refchk)
 166 {
 167         struct list_head                worklist;
 168         struct xchk_refcnt_frag         *frag;
 169         struct xchk_refcnt_frag         *n;
 170         xfs_agblock_t                   bno;
 171         xfs_agblock_t                   rbno;
 172         xfs_agblock_t                   next_rbno;
 173         xfs_nlink_t                     nr;
 174         xfs_nlink_t                     target_nr;
 175
 176         target_nr = refchk->refcount - refchk->seen;
 177         if (target_nr == 0)
 178                 return;
 179
 180         /*
 181          * There are (refchk->rc.rc_refcount - refchk->nr refcount)
 182          * references we haven't found yet.  Pull that many off the
 183          * fragment list and figure out where the smallest rmap ends
 184          * (and therefore the next rmap should start).  All the rmaps
 185          * we pull off should start at or before the beginning of the
 186          * refcount record's range.
 187          */
 188         INIT_LIST_HEAD(&worklist);
 189         rbno = NULLAGBLOCK;
 190
 191         /* Make sure the fragments actually /are/ in agbno order. */
 192         bno = 0;
 193         list_for_each_entry(frag, &refchk->fragments, list) {
 194                 if (frag->rm.rm_startblock < bno)
 195                         goto done;
 196                 bno = frag->rm.rm_startblock;
 197         }
 198
 199         /*
 200          * Find all the rmaps that start at or before the refc extent,
 201          * and put them on the worklist.
 202          */
 203         nr = 0;
 204         list_for_each_entry_safe(frag, n, &refchk->fragments, list) {
 205                 if (frag->rm.rm_startblock > refchk->bno || nr > target_nr)
 206                         break;
 207                 bno = frag->rm.rm_startblock + frag->rm.rm_blockcount;
 208                 if (bno < rbno)
 209                         rbno = bno;
 210                 list_move_tail(&frag->list, &worklist);
 211                 nr++;
 212         }
 213
 214         /*
 215          * We should have found exactly $target_nr rmap fragments starting
 216          * at or before the refcount extent.
 217          */
 218         if (nr != target_nr)
 219                 goto done;
 220
 221         while (!list_empty(&refchk->fragments)) {
 222                 /* Discard any fragments ending at rbno from the worklist. */
 223                 nr = 0;
 224                 next_rbno = NULLAGBLOCK;
 225                 list_for_each_entry_safe(frag, n, &worklist, list) {
 226                         bno = frag->rm.rm_startblock + frag->rm.rm_blockcount;
 227                         if (bno != rbno) {
 228                                 if (bno < next_rbno)
 229                                         next_rbno = bno;
 230                                 continue;
 231                         }
 232                         list_del(&frag->list);
 233                         kfree(frag);
 234                         nr++;
 235                 }
 236
 237                 /* Try to add nr rmaps starting at rbno to the worklist. */
 238                 list_for_each_entry_safe(frag, n, &refchk->fragments, list) {
 239                         bno = frag->rm.rm_startblock + frag->rm.rm_blockcount;
 240                         if (frag->rm.rm_startblock != rbno)
 241                                 goto done;
 242                         list_move_tail(&frag->list, &worklist);
 243                         if (next_rbno > bno)
 244                                 next_rbno = bno;
 245                         nr--;
 246                         if (nr == 0)
 247                                 break;
 248                 }
 249
 250                 /*
 251                  * If we get here and nr > 0, this means that we added fewer
 252                  * items to the worklist than we discarded because the fragment
 253                  * list ran out of items.  Therefore, we cannot maintain the
 254                  * required refcount.  Something is wrong, so we're done.
 255                  */
 256                 if (nr)
 257                         goto done;
 258
 259                 rbno = next_rbno;
 260         }
 261
 262         /*
 263          * Make sure the last extent we processed ends at or beyond
 264          * the end of the refcount extent.
 265          */
 266         if (rbno < refchk->bno + refchk->len)
 267                 goto done;
 268
 269         /* Actually record us having seen the remaining refcount. */
 270         refchk->seen = refchk->refcount;
 271 done:
 272         /* Delete fragments and work list. */
 273         list_for_each_entry_safe(frag, n, &worklist, list) {
 274                 list_del(&frag->list);
 275                 kfree(frag);
 276         }
 277         list_for_each_entry_safe(frag, n, &refchk->fragments, list) {
 278                 list_del(&frag->list);
 279                 kfree(frag);
 280         }
 281 }
 282
 283 /* Use the rmap entries covering this extent to verify the refcount. */
 284 STATIC void
 285 xchk_refcountbt_xref_rmap(
 286         struct xfs_scrub                *sc,
 287         const struct xfs_refcount_irec  *irec)
 288 {
 289         struct xchk_refcnt_check        refchk = {
 290                 .sc                     = sc,
 291                 .bno                    = irec->rc_startblock,
 292                 .len                    = irec->rc_blockcount,
 293                 .refcount               = irec->rc_refcount,
 294                 .seen = 0,
 295         };
 296         struct xfs_rmap_irec            low;
 297         struct xfs_rmap_irec            high;
 298         struct xchk_refcnt_frag         *frag;
 299         struct xchk_refcnt_frag         *n;
 300         int                             error;
 301
 302         if (!sc->sa.rmap_cur || xchk_skip_xref(sc->sm))
 303                 return;
 304
 305         /* Cross-reference with the rmapbt to confirm the refcount. */
 306         memset(&low, 0, sizeof(low));
 307         low.rm_startblock = irec->rc_startblock;
 308         memset(&high, 0xFF, sizeof(high));
 309         high.rm_startblock = irec->rc_startblock + irec->rc_blockcount - 1;
 310
 311         INIT_LIST_HEAD(&refchk.fragments);
 312         error = xfs_rmap_query_range(sc->sa.rmap_cur, &low, &high,
 313                         &xchk_refcountbt_rmap_check, &refchk);
 314         if (!xchk_should_check_xref(sc, &error, &sc->sa.rmap_cur))
 315                 goto out_free;
 316
 317         xchk_refcountbt_process_rmap_fragments(&refchk);
 318         if (irec->rc_refcount != refchk.seen) {
 319                 trace_xchk_refcount_incorrect(sc->sa.pag, irec, refchk.seen);
 320                 xchk_btree_xref_set_corrupt(sc, sc->sa.rmap_cur, 0);
 321         }
 322
 323 out_free:
 324         list_for_each_entry_safe(frag, n, &refchk.fragments, list) {
 325                 list_del(&frag->list);
 326                 kfree(frag);
 327         }
 328 }
 329
 330 /* Cross-reference with the other btrees. */
 331 STATIC void
 332 xchk_refcountbt_xref(
 333         struct xfs_scrub                *sc,
 334         const struct xfs_refcount_irec  *irec)
 335 {
 336         if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
 337                 return;
 338
 339         xchk_xref_is_used_space(sc, irec->rc_startblock, irec->rc_blockcount);
 340         xchk_xref_is_not_inode_chunk(sc, irec->rc_startblock,
 341                         irec->rc_blockcount);
 342         xchk_refcountbt_xref_rmap(sc, irec);
 343 }
 344
 345 struct xchk_refcbt_records {
 346         /* Previous refcount record. */
 347         struct xfs_refcount_irec prev_rec;
 348
 349         /* The next AG block where we aren't expecting shared extents. */
 350         xfs_agblock_t           next_unshared_agbno;
 351
 352         /* Number of CoW blocks we expect. */
 353         xfs_agblock_t           cow_blocks;
 354
 355         /* Was the last record a shared or CoW staging extent? */
 356         enum xfs_refc_domain    prev_domain;
 357 };
 358
 359 STATIC int
 360 xchk_refcountbt_rmap_check_gap(
 361         struct xfs_btree_cur            *cur,
 362         const struct xfs_rmap_irec      *rec,
 363         void                            *priv)
 364 {
 365         xfs_agblock_t                   *next_bno = priv;
 366
 367         if (*next_bno != NULLAGBLOCK && rec->rm_startblock < *next_bno)
 368                 return -ECANCELED;
 369
 370         *next_bno = rec->rm_startblock + rec->rm_blockcount;
 371         return 0;
 372 }
 373
 374 /*
 375  * Make sure that a gap in the reference count records does not correspond to
 376  * overlapping records (i.e. shared extents) in the reverse mappings.
 377  */
 378 static inline void
 379 xchk_refcountbt_xref_gaps(
 380         struct xfs_scrub        *sc,
 381         struct xchk_refcbt_records *rrc,
 382         xfs_agblock_t           bno)
 383 {
 384         struct xfs_rmap_irec    low;
 385         struct xfs_rmap_irec    high;
 386         xfs_agblock_t           next_bno = NULLAGBLOCK;
 387         int                     error;
 388
 389         if (bno <= rrc->next_unshared_agbno || !sc->sa.rmap_cur ||
 390             xchk_skip_xref(sc->sm))
 391                 return;
 392
 393         memset(&low, 0, sizeof(low));
 394         low.rm_startblock = rrc->next_unshared_agbno;
 395         memset(&high, 0xFF, sizeof(high));
 396         high.rm_startblock = bno - 1;
 397
 398         error = xfs_rmap_query_range(sc->sa.rmap_cur, &low, &high,
 399                         xchk_refcountbt_rmap_check_gap, &next_bno);
 400         if (error == -ECANCELED)
 401                 xchk_btree_xref_set_corrupt(sc, sc->sa.rmap_cur, 0);
 402         else
 403                 xchk_should_check_xref(sc, &error, &sc->sa.rmap_cur);
 404 }
 405
 406 static inline bool
 407 xchk_refcount_mergeable(
 408         struct xchk_refcbt_records      *rrc,
 409         const struct xfs_refcount_irec  *r2)
 410 {
 411         const struct xfs_refcount_irec  *r1 = &rrc->prev_rec;
 412
 413         /* Ignore if prev_rec is not yet initialized. */
 414         if (r1->rc_blockcount > 0)
 415                 return false;
 416
 417         if (r1->rc_domain != r2->rc_domain)
 418                 return false;
 419         if (r1->rc_startblock + r1->rc_blockcount != r2->rc_startblock)
 420                 return false;
 421         if (r1->rc_refcount != r2->rc_refcount)
 422                 return false;
 423         if ((unsigned long long)r1->rc_blockcount + r2->rc_blockcount >
 424                         XFS_REFC_LEN_MAX)
 425                 return false;
 426
 427         return true;
 428 }
 429
 430 /* Flag failures for records that could be merged. */
 431 STATIC void
 432 xchk_refcountbt_check_mergeable(
 433         struct xchk_btree               *bs,
 434         struct xchk_refcbt_records      *rrc,
 435         const struct xfs_refcount_irec  *irec)
 436 {
 437         if (bs->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
 438                 return;
 439
 440         if (xchk_refcount_mergeable(rrc, irec))
 441                 xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
 442
 443         memcpy(&rrc->prev_rec, irec, sizeof(struct xfs_refcount_irec));
 444 }
 445
 446 /* Scrub a refcountbt record. */
 447 STATIC int
 448 xchk_refcountbt_rec(
 449         struct xchk_btree       *bs,
 450         const union xfs_btree_rec *rec)
 451 {
 452         struct xfs_refcount_irec irec;
 453         struct xchk_refcbt_records *rrc = bs->private;
 454
 455         xfs_refcount_btrec_to_irec(rec, &irec);
 456         if (xfs_refcount_check_irec(to_perag(bs->cur->bc_group), &irec) !=
 457                         NULL) {
 458                 xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
 459                 return 0;
 460         }
 461
 462         if (irec.rc_domain == XFS_REFC_DOMAIN_COW)
 463                 rrc->cow_blocks += irec.rc_blockcount;
 464
 465         /* Shared records always come before CoW records. */
 466         if (irec.rc_domain == XFS_REFC_DOMAIN_SHARED &&
 467             rrc->prev_domain == XFS_REFC_DOMAIN_COW)
 468                 xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
 469         rrc->prev_domain = irec.rc_domain;
 470
 471         xchk_refcountbt_check_mergeable(bs, rrc, &irec);
 472         xchk_refcountbt_xref(bs->sc, &irec);
 473
 474         /*
 475          * If this is a record for a shared extent, check that all blocks
 476          * between the previous record and this one have at most one reverse
 477          * mapping.
 478          */
 479         if (irec.rc_domain == XFS_REFC_DOMAIN_SHARED) {
 480                 xchk_refcountbt_xref_gaps(bs->sc, rrc, irec.rc_startblock);
 481                 rrc->next_unshared_agbno = irec.rc_startblock +
 482                                            irec.rc_blockcount;
 483         }
 484
 485         return 0;
 486 }
 487
 488 /* Make sure we have as many refc blocks as the rmap says. */
 489 STATIC void
 490 xchk_refcount_xref_rmap(
 491         struct xfs_scrub        *sc,
 492         xfs_filblks_t           cow_blocks)
 493 {
 494         xfs_filblks_t           refcbt_blocks = 0;
 495         xfs_filblks_t           blocks;
 496         int                     error;
 497
 498         if (!sc->sa.rmap_cur || xchk_skip_xref(sc->sm))
 499                 return;
 500
 501         /* Check that we saw as many refcbt blocks as the rmap knows about. */
 502         error = xfs_btree_count_blocks(sc->sa.refc_cur, &refcbt_blocks);
 503         if (!xchk_btree_process_error(sc, sc->sa.refc_cur, 0, &error))
 504                 return;
 505         error = xchk_count_rmap_ownedby_ag(sc, sc->sa.rmap_cur,
 506                         &XFS_RMAP_OINFO_REFC, &blocks);
 507         if (!xchk_should_check_xref(sc, &error, &sc->sa.rmap_cur))
 508                 return;
 509         if (blocks != refcbt_blocks)
 510                 xchk_btree_xref_set_corrupt(sc, sc->sa.rmap_cur, 0);
 511
 512         /* Check that we saw as many cow blocks as the rmap knows about. */
 513         error = xchk_count_rmap_ownedby_ag(sc, sc->sa.rmap_cur,
 514                         &XFS_RMAP_OINFO_COW, &blocks);
 515         if (!xchk_should_check_xref(sc, &error, &sc->sa.rmap_cur))
 516                 return;
 517         if (blocks != cow_blocks)
 518                 xchk_btree_xref_set_corrupt(sc, sc->sa.rmap_cur, 0);
 519 }
 520
 521 /* Scrub the refcount btree for some AG. */
 522 int
 523 xchk_refcountbt(
 524         struct xfs_scrub        *sc)
 525 {
 526         struct xchk_refcbt_records rrc = {
 527                 .cow_blocks             = 0,
 528                 .next_unshared_agbno    = 0,
 529                 .prev_domain            = XFS_REFC_DOMAIN_SHARED,
 530         };
 531         int                     error;
 532
 533         error = xchk_btree(sc, sc->sa.refc_cur, xchk_refcountbt_rec,
 534                         &XFS_RMAP_OINFO_REFC, &rrc);
 535         if (error)
 536                 return error;
 537
 538         /*
 539          * Check that all blocks between the last refcount > 1 record and the
 540          * end of the AG have at most one reverse mapping.
 541          */
 542         xchk_refcountbt_xref_gaps(sc, &rrc, sc->mp->m_sb.sb_agblocks);
 543
 544         xchk_refcount_xref_rmap(sc, rrc.cow_blocks);
 545
 546         return 0;
 547 }
 548
 549 /* xref check that a cow staging extent is marked in the refcountbt. */
 550 void
 551 xchk_xref_is_cow_staging(
 552         struct xfs_scrub                *sc,
 553         xfs_agblock_t                   agbno,
 554         xfs_extlen_t                    len)
 555 {
 556         struct xfs_refcount_irec        rc;
 557         int                             has_refcount;
 558         int                             error;
 559
 560         if (!sc->sa.refc_cur || xchk_skip_xref(sc->sm))
 561                 return;
 562
 563         /* Find the CoW staging extent. */
 564         error = xfs_refcount_lookup_le(sc->sa.refc_cur, XFS_REFC_DOMAIN_COW,
 565                         agbno, &has_refcount);
 566         if (!xchk_should_check_xref(sc, &error, &sc->sa.refc_cur))
 567                 return;
 568         if (!has_refcount) {
 569                 xchk_btree_xref_set_corrupt(sc, sc->sa.refc_cur, 0);
 570                 return;
 571         }
 572
 573         error = xfs_refcount_get_rec(sc->sa.refc_cur, &rc, &has_refcount);
 574         if (!xchk_should_check_xref(sc, &error, &sc->sa.refc_cur))
 575                 return;
 576         if (!has_refcount) {
 577                 xchk_btree_xref_set_corrupt(sc, sc->sa.refc_cur, 0);
 578                 return;
 579         }
 580
 581         /* CoW lookup returned a shared extent record? */
 582         if (rc.rc_domain != XFS_REFC_DOMAIN_COW)
 583                 xchk_btree_xref_set_corrupt(sc, sc->sa.refc_cur, 0);
 584
 585         /* Must be at least as long as what was passed in */
 586         if (rc.rc_blockcount < len)
 587                 xchk_btree_xref_set_corrupt(sc, sc->sa.refc_cur, 0);
 588 }
 589
 590 /*
 591  * xref check that the extent is not shared.  Only file data blocks
 592  * can have multiple owners.
 593  */
 594 void
 595 xchk_xref_is_not_shared(
 596         struct xfs_scrub        *sc,
 597         xfs_agblock_t           agbno,
 598         xfs_extlen_t            len)
 599 {
 600         enum xbtree_recpacking  outcome;
 601         int                     error;
 602
 603         if (!sc->sa.refc_cur || xchk_skip_xref(sc->sm))
 604                 return;
 605
 606         error = xfs_refcount_has_records(sc->sa.refc_cur,
 607                         XFS_REFC_DOMAIN_SHARED, agbno, len, &outcome);
 608         if (!xchk_should_check_xref(sc, &error, &sc->sa.refc_cur))
 609                 return;
 610         if (outcome != XBTREE_RECPACKING_EMPTY)
 611                 xchk_btree_xref_set_corrupt(sc, sc->sa.refc_cur, 0);
 612 }
 613
 614 /* xref check that the extent is not being used for CoW staging. */
 615 void
 616 xchk_xref_is_not_cow_staging(
 617         struct xfs_scrub        *sc,
 618         xfs_agblock_t           agbno,
 619         xfs_extlen_t            len)
 620 {
 621         enum xbtree_recpacking  outcome;
 622         int                     error;
 623
 624         if (!sc->sa.refc_cur || xchk_skip_xref(sc->sm))
 625                 return;
 626
 627         error = xfs_refcount_has_records(sc->sa.refc_cur, XFS_REFC_DOMAIN_COW,
 628                         agbno, len, &outcome);
 629         if (!xchk_should_check_xref(sc, &error, &sc->sa.refc_cur))
 630                 return;
 631         if (outcome != XBTREE_RECPACKING_EMPTY)
 632                 xchk_btree_xref_set_corrupt(sc, sc->sa.refc_cur, 0);
 633 }